The office furniture industry has, in recent years, extensively utilized systems employing serially-connected upright wall panels having channel-like raceways secured along the lower edges thereof for confining electrical and/or communication cables. These raceways have assumed many forms and configurations, but have typically required either openable or removable side covers so as to provide access to the interior of the raceway. One such system is disclosed in U.S. Pat. No. 4,277,123, owned by the assignee of this application.
To improve upon the structure of such raceway, attempts have been made to mold the raceway as an integral one-piece arrangement employing integral hinges associated with the lower corner so as to permit the side walls of the raceway to be selectively pivotally moved and hence function as openable side covers. One such raceway is illustrated by U.S. Pat. No. 4,463,046. This latter patent discloses a one-piece molded raceway of channel-like configuration having side and bottom walls of a rigid plastics material, with flexible plastic hinges being integrally molded in the channel at the lower corners. The hinges are of a laminate construction in that the rigid material of the walls defines an inner layer having a longitudinally extending notch therein, and an outer layer of a more flexible plastic material is disposed directly thereover, this laminate being integrally molded in a single operation. By flexing the side wall, this effects breakage of the rigid inner layer along the notch, and hence permits the outer more flexible layer to function as a so called "living" hinge. The hinge arrangement of this patent is desirable since the rigid inner layer does permit the dimensional tolerances of the raceway to be rather precisely maintained during the extrusion process. However, assembly of the raceway on the panel is difficult since the installer must initially break each hinge (i.e., break the inner layer) before installing the raceway on the panel. Further, after the hinge is broken, the resulting hinge is formed solely by the outer flexible layer, which layer has a thickness which is only about one-half the thickness of the wall structure defining the raceway. Such hinge is thus believed to possess a much shorter life in terms of the number of successful flexing cycles which it is capable of performing. Also, the side cover always tends to swing back toward its closed position, and hence this interfers with the installing of cables into the raceway.
Accordingly, the present invention relates to a raceway of the aforementioned type, which raceway is believed to represent an improvement over known structures of this type. This invention also relates to an improved method of making the raceway so as to provide for close dimensional tolerances during the manufacturing process, while at the same time resulting in a raceway having an integral hinge possessing significantly improved flexibility and life.
In the improved raceway of the present invention, the rigid plastic side covers are joined to the rigid plastic bottom wall through integral plastic hinges which are flexible. The hinges extend across the complete thickness of the raceway wall so as to optimize both the securement of the flexible hinge material to the rigid wall material, and at the same time optimize the life and flexibility of the hinge. The hinge of flexible material has, in the preferred embodiment, a configuration which provides an increased mass of flexible material (i.e. increased width) adjacent one side of the raceway wall in relationship to the other side so as to provide increased flexible capability adjacent one side of the raceway, which in effect define an imaginary hingepoint adjacent the other side of the raceway wall to thereby more readily accommodate the flexing of the side cover relative to the bottom wall.
The improved raceway of this invention is manufactured by an improved process wherein the raceway is initially formed, as by an extrusion technique, in one piece so that the rigid plastic walls and the hinges of flexible plastic material are integrally joined together during the extrusion process. The hinge initially has an extension which projects outwardly beyond one of the side surfaces of the raceway, and this extension is surrounded by a channel-like bridge of rigid plastic material which integrally joins to the rigid plastic panels on opposite sides of the flexible hinge. This bridge and extension are formed integrally with the raceway during the extrusion step so that the rigid bridge maintains close dimensional tolerances across the flexible hinge. Upon discharge from the extruder, and while the extrusion is still warm and relatively soft, the extruded raceway is moved directly past a cutting device which severs the rigid bridge and the flexible extension from the raceway so as to leave a substantially flush surface, whereby the flexible hinge then extends across the full thickness of the raceway and the adjacent rigid panels are integrally joined together solely through the intermediate flexible hinge.
Other objects and purposes of the invention will be apparent to persons familiar with structures of this general type upon reading the following specification and inspecting the accompanying drawings.